Ratchet and pawl mechanism



June 5, 1945. WALLER 2,377,733

RATCHET AND PAWL MEQCHANFSMS Filed Dec. 9, 1943 ATTORNEY Patented June5, 1945 RATcriEr AND PAWL MECHANISM Fred Waller, Huntington, N. Y.,assignbrtoTh Vitarama Corporation, Longlsland a corporation of New YorkApplication December 9. 194$.Seria1No. 513,61 I io claims. (Cl. "7j4 IThis invention relates to ratchet and pawl. mechanisms. i

.It is an object of ratchet and pawl mechanism which maybe perated athigh speed, accurately and Without the, invention to provide aoverthrow, and which is adapted to operate satisfactorily, both for.movements of relatively small and relatively large amplitude.

Other objects and advantages of the invention will appear hereinafter. 1

A preferred embodiment of the-invention se lected for purposes of,illustration is shown. in the accompanying drawing, in which,

Figure 1 is a top plan view of the mechanism. Figure 2 is afrontelevation, and c I A Figure 3 is .a front elevation of a modifiedform.

Referring to Figures 1 and 2, thein ve n tion is illustratedas appliedto a ratchet wheel I which is rotatably mounted ona shaft 2, andin whichthe ratchet teeth 3 are closelyspaced, as for example, in which theteeth are spaced at .02" or pivoted on the shaft 2, but the member lishould be so mounted as to have slight frictional resistance to movementin either direction.

in any suitable manner, but in the embodiment illustrated is providedwith a relatively long arm I5 which is pivotally mounted at IS. Themember I3. and detent are normally held in engagement with the ratchetWheel by the spring H.

.The pawl isalso provided with a lever arm I8 having a pin I9 mounted tocooperate with the cam surface I4. Thus, when the solenoid is enervgized because of the slightfrictional resistance to movement oi theidler member 6, the initial forward movement of the lever arm I causesthe pawl to pivot on the idlermember 6 to engage a'tooth of the ratchetwheel, and causes the lever arm I 8 to lift the member I3 and the detentI2'to'free f thecratchet wheel. Subsequent forward movenient of thelever arm 1 causes the idler member 6 The pawl is provided with a leverarm I extending substantially at right angles to the pawl,

and the lever arm is-connected in any suitable manner with suitableactuating means such as the armature 8 of the solenoid 9., The lever armI is also connected to a spring I0 adapted to return the pawl to normalposition after actuation, and. carries a pin l I positioned to engagethe idler member 6 to return said member to normal position afteractuation. r I

A holding detent I2 is also provided, said detent being mounted on amember l3 having acurved cam surface I 4 concentric with the toothed,rim of the ratchet wheel. The member I3 is mounted to move outwardly torelease the detent. The movement of the member I3 required to releasethe detent is small and does not substantially alter the concentricrelationship between the cam surface and the rim of the ratchet wheel,but if desired the cam surface may be formed so as to be concentric withthe rim of the ratchet wheel when the member I3 is in raised positiomasit is in this position that the cam surfaceis utilized as herein.-

after explained; The member l3 may be'mounted to advance with the pawl,whichremainsin engagement with the ratchet tooth, thus advancing theratchet wheel. At the same time, the pin I9,

riding along the concentric cam surface I4 retains the detent out ofengagement with the ratchet I wheel. When the solenoid is deenergized,the initial backward movement of the lever arm I under the influence ofthe spring I0 causes the pawl to pivot on the idler member 6 to lift thepawl out of; engagement with the ratchet Wheel, and causes the lever armI9 to move downwardly, allowing the member I3 and detent to movedownwardlyunder theinfluence of the spring I 1 to reengage theratchetwheel. Subsequent backward movement of the lever arm causes thepin to engage the idler member 6 to return it to its initial position. c1 l c i It will be observed that the pawl must be fully engaged with theratchet wheel before any advancing movement can take place. Likewise theadvancing movement must have ceased before the pawl can be released fromthe ratchet wheel. Furthermore, the arrangement of the parts is suchthat on the advancing stroke the detent is not released from the ratchetwheel until the pawl is in engagement therewith, and on the returnstroke the pawl is not released from the ratchet when until the detentisin engagement therewith. q c I r 3' Means may be provided to limit theamplitude of movement of the idler member, and in consequence theamplitude of movement ofthe pawl, such means comprising, in theembodimentillustrated a limit stop 20 pivoted at 2| so that it may bemoved into or out of position to limit the movement. In the embodimentillustrated the limit stop is set to permit the ratchet wheel to be ad-In the embodimentillustrated in Figures 1 and 2 the mechanism is adaptedfor two way operation, that is, to rotate the ratchet wheel in clockwiseor counter-clockwise direction. Thus, the pawl 4' and idler 6' areprovided and the member I3 is extended at 13' to provide acam surface V[4. The pawl is provided with lever arms 1 and I8 and said armslareprovidedwith pins. l l. and I9, all of'said partsfunctioning astheircounterparts previously described. The spring in is also connected tothe arm 1' so that when the arm] is moved the arm 1' serves as a fixedsupport for the other end of the spring andjilicef'versa.

In Figure 3, the invention is illustrated as adapted for use inconnection"withzalstraight variously modified and embodied within thescope of the -subjoined claims.

I claim as my invention: 1. Ratchet mechanism comprising in combination, a ratchet provided with teeth movable along a fixed path, a pawlmounted upon an idler member for a first movement normal to saidteeth.forvengagementfland disengagement therewith and l for a secondimovementwith ther ifidler member along a path parallel to that of the teeth foradvancing the ratchet, a detent mounted for movement normal to saidteeth for engagement arid disengagement therewith for holding theratchet bar 3| having ratchet teeth 33. A feed pawl 34 is pivoted at 35on an idler slide 36 having slots 50 allowing the desired ampl-itu'de'oflongitudinal motion on the guide pins ,The motion of the slide, ofcourse, is parallel to the mo- ;tion: :of the ratchet :sbar, :buttthesslidesshould' :be ,so:mountedaasito :havenslight'frictionakresistancetoimovement.

.Thetpawl :is provided rw-ith' awleveroarm flaextendinglsubstantiallyoatrrightangles: to the pawl, zand the I lever amris'zconnectedszinz anytsuitable .manner with wsuitable f'actuatingzmeansa suchwsas the-armature -38wof i thevsolen'oid F39. JThQ! lever arm:31 :-;;isalso :connecteflzto; arspringdn za-dapted toxretum .the; pawlto :normalt position'rafterr ac- .turn the. slide.

g A: holding detent-42. isoalsolprovided, ;said fideltent being amounted on :a member e43 iiaaving 1-2. .ca-m .-surace '44 :tparallel tothe z-toothed :-:edge.-.:of

the vratchet tbar. 'I'he :mem'ber v43 zis 'slidab'ly mounted-tomove-vertically tovrelease .thetdetent, .being; .provi/ded for: thispurposewvitlmslotsM'Snengagin lguidel pins--46. :The'- member :flzand:de- ,tentA2 1 are normally :held :inwengagement with theratchet barby-zthespring-Al. Y

r{The paw1..;isalso; provided with ailever arm-#48 having a pin 49mounted :to vcooperate z'withcthe cam'surfacedd. .Thus-whenthBz-SGIGHOidjYiSJG EF- ,giaed,zheoauseeofttheslight,frictionalrresistance tolmovement'of whet-slide :36, the: initialforward movement .ofrthel lever iarmr3 1 ;causesl therpaiwlzto pivot tonthe .id-le'rnslide r36 Zto=:en;gage :a tooth of the ratchetbareandacausesfitherpin M9,";onZ lever armfllllsto alift. thermemberifltiandttheudetentan to free tthe ratchet bar. SubsequentL'fomvard movementof tthe-rleverz arm #31 1 causes cthezisd-ler slide 36to advance with the pawl, whichammains in engagement with -st-helratchetttooth thus tadvanci-ng the #ratchetobar. o-htithessazme'timetthe pin. AQ-Lr-iding along the cam :surface :64 :retains the v .cletent o-ut f --lengagement withzthe :rratchet bar. IVhenthe solenoidis.deenergizedgtheinitial backward move-ment .of the :lever arm3'hxrm'der the influence of -the-sspring r450 :causesc-the pawl to pivoton; the, idler--s1-ideh36 ,todittttheiqaawleout of engagement-with the"ratehetkbar causes the lever warm *4 9 :to 2 move :kiownwafidlyeallowing tlie member -1t3 ;=-and;detent M2 :to -emove downwardly toreengage the ratchet bar. Subsequent back wardtmovementi of.thelevenarrn'reimrns theslide 3-6: to its 1 initialt positio n.

,nln the? embodiment illustrated in Figure 3 the pawl: and "detent arealigne d 'to'engage thesaine tooth ioftthe irratohet 'bar,as"tlris'arran,gerrrent' is frequently advantageous. It "will" be"understood, however, that the pawl may belocated either' in front of orbehin d theidtent,"if'desired.

lt will 'be understoodithatthe invention maybe ratchet except .while itis-being advanced, and .interacting means "between said pawl and detent.fforaactuatinglthe.idetent during the first movement of the pawl,

2'. Ratc-heir mechanism comprising in combination, a ratchet providedwith teeth movable along a'fixe'd path, a pawl mounted upon an idlermemtimer 1 for ta firstzrmovement normal .1110 ws'aida-teth forengagement and disengagement,therewitlrsand for a 'ssecond rmoveme'ntwith the idler: menrber along-r aipath:parallel'ztorthatvofi the teethiforsadwarming the: ratchetga: detent mounted for rmovement :tnormal i totssaid zteethxfor i'engagement zand disengagement:therewith;forrholdingt'he' ratchet except while :it :is sbeing raidvanced, azandinteriactingr means tbet weenrsaid pawlrarrd i detent Ifor actuating thedetent duringtthezfirstizmovement lof-a the :pawLosa-i'd detentactuatingmeans lnclud- :izllgrazcaim :and rcam foll'ower having: relative"sliding movement during lthe iratchet la'dvancing m-ovementioftsaidpawl.

3. Ratchet mechanism;comprisingrin combina- .tlOILmi-L -i-atchet zhavingcan :engageable feed ele ment movable along a fixed path, a pawlmounted a ng:movementiandsaasecondtor advancing and :returnzm'overnent-,:.a'etuat-ing' means connect-ed to said pawltoifirstzrengage and advaneeit anwthen ltaiseaarrd'*return itgathetent-mounted*"f-or "an en gagingzaiodzdisengaging-movementrelativetosaid ratchet tt-eth, -an d earn "and cam follower means operativelyarranged"between'said "pawl and Tdetentforraismg the detent whenthepawldsengaged, ho lding the detent raised "as Vthe,paw1advancosadropping the-"'detentwhenfthe pawl is reengage'ii, an'd leaving"the ;detent, 'down while the-pawlreturns; .j. I r i i'l 5. Apparatus"as 'set'fforth in .claim .4,,.w icn further includes" an element,carriedsby isaidlzpawl 'for'returnin'g said idler whenthelpavrlmeturns.

*"6..Apparatus as .sett'forthlinoclai-m l, :which iu-rtl rer includes aoreversely acting ,1 pawl ,1- idler, actuating means, and eam .and rcamfollower means associatedtwith saidlrlatchet: and idetent'.

v 'Ratchetnnechanism.eomprisingdn-scombina tion,;a ratchetwheel,anlidlerrcoaxiallyimolmted alongsidethe wheel, a pawl pivoted on saididler,

an arm on said pawl extending alongside an arm of said idler, actuatingmeans connected, to said pawl arm, a pin on said pawl arm for returningthe idler with the pawl, a detent, a cam connected to the, detent, and acam operating arm on said pawl forfirst raising and then sliding alongsaid cam.

8. Ratchet mechanism as set forth in claim '7, which further includes areversely acting pawl,

idler, actuating means, and cam and cam operating means associated withsaid ratchet and detent. i

9. Ratchet mechanism as set forth in claim 7,

which further includes a reversely acting pawl, idler, actuating means,and cam and cam oper-.

ating means associated with said ratchet and detent, said actuatingmeans for the two pawls including oppositely disposed power devices anda common return spring, secured, between the power devices. l

10. Apparatus as set forth in claim 4 in which 10 said ratchet andidlermove rectilineally.

FRED

